Device for launching a projectile or a launch object in general

ABSTRACT

A device ( 1 ) for launching a projectile, comprising: a stock ( 2 ); at least two bending members ( 10 ) associated to said stock ( 2 ) on opposite sides thereof; tensioning means ( 323 ) of said bending members ( 10 ), comprising at least two cams ( 323 ) arranged on opposite sides of the stock ( 2 ), each of which is pivoted at a respective first axis of rotation ( 33 ) and is associated to at least one corresponding bending member ( 10 ); pushing means ( 30 ) of said projectile apt to cooperate with said bending members ( 10 ) comprising at least two pushing arms ( 32 ) arranged on opposite sides of the stock ( 2 ) and connected to each other through a flexible pushing member ( 31 ) wherein each of said pushing arms ( 32 ) is pivoted at a respective axis of rotation ( 33 ) and is apt to support a portion of said flexible pushing member ( 31 ), each of said pushing arms ( 32 ) being operatively connected to a respective cam ( 323 ), wherein said device ( 1 ) further comprises a flexible force member ( 37 ) for commanding a rotation of a pushing arm ( 32 ), and two pairs of pulleys ( 145, 146 ) arranged on opposite sides of the stock ( 2 ), wherein each pair comprises a first pulley ( 145 ) interposed between a respective pushing arm ( 32 ).

The present disclosure refers to a device for launching a projectile, or an arrow, or a bolt, or a launch object in general. More specifically, it refers to a perfected type of archery crossbow.

Several types of devices for launching a projectile are already known, both for sports and amateur uses, and for professional uses. Among these, there are, in particular, crossbows, generally consisting of a bow (in wood, metal, plastic or composite material, e.g. including glass or carbon fiber) apt to accumulate elastic energy and return it to the projectile to be launched, a propulsive wire for pushing the projectile, a fastening system to keep said wire in the loaded position and then release it, a stock secured to said bow and comprising a support-guide for the projectile.

The modern devices for launching a projectile usually have a bow divided into two bending members (i.e. flexing members, also called limbs) which are identical (left and right) and secured to a central handle member (also called riser) or to the stock of the device.

In some embodiments (e.g. U.S. Pat. No. 3,854,467; U.S. Pat. No. 3,923,035; U.S. Pat. No. 3,987,777), there are pulleys pivoted to the free ends of the bending members and pulleys pivoted to a central member; the pulleys include tracks on which a propulsive wire is partially wound. Under the most common arrangement, a propulsive wire is connected to one pulley and to its symmetrically opposite one on the other side; each one of said pulleys is integral to a smaller pulley, which holds one end of another wire, whose other end is connected to the opposite limb. Some of the pulleys may have an eccentric profile.

The traction of the propulsive wire turns the pulleys, unwinding the propulsive wire from some pulleys, while at the same time the other wires are wound around other pulleys; this causes the flexing of the bending members and the accumulation of elastic energy. Thanks to an adequate profiling of the pulley tracks and an appropriate eccentricity of the same, in these devices it is possible to reduce the maximum force which must be exerted by the user during the loading of the device and to increase the ratio between the stroke of the projectile (also called “draw length”) and the movement of the ends of the bending members.

Other embodiments of devices for the launching of projectiles comprising pulleys or the like for a similar purpose are disclosed, for example, in U.S. Pat. No. 5,388,564, U.S. Pat. No. 5,499,618, U.S. Pat. No. 5,967,132. Embodiments of a crossbow comprising pulleys are disclosed, for example, in U.S. Pat. No. 5,630,405 and U.S. Pat. No. 6,155,243.

One of the main disadvantages of the devices of known art and, in particular, of crossbows of known art, is that, during the launch phase, the bending members, the propulsive wire and any pulleys arrive at the end of the stroke with a high residual kinetic energy, proportional to the masses in movement; because of the very structure of the device, this energy must be dissipated in a very short space or even in no space, as the components in motion have already reached the end of their possible stroke. The stopping of the components in motion after the launch is, therefore, quite sudden and subjects the entire device to an end-of-stroke shock which involves very high stresses, discharging the residual energy on the wires and stressing the pivots of the pulleys and the bending members. Indeed, in the case of dry firing (that is, no projectile is fired), there is no transfer of energy to a free mass and the stresses may be so high as to break the device.

This dictates structural constraints in the dimensioning of the device, imposes practical limits on the projectile mass that can be launched safely and imposes very high levels of attention and expertise on the user, who could damage the crossbow or even get injured in case of dry firing or of using too light a projectile.

In the case of said more advanced devices, the problem is actually accentuated by the presence of the pulleys at the ends of the bending members, as this considerably increases the masses, the kinetic energy and the moments of inertia in play. In addition, the sudden stop at the end of the stroke is the main cause of the noise produced during the use of these devices for launching a projectile.

Another disadvantage of the devices of known art is the fact that, even when the device is in the initial position, the bending members are in a tensioned state; among other things, this makes it necessary to use specific tools, such as a press, in order to carry out maintenance operations such as the replacement of the propulsive wire.

Finally, it must be noted that possible differences, even slight ones, in the elastic characteristics of the right and left bending members may be the cause of asymmetries in the thrust exercised on the projectile and, therefore, compromise the launch accuracy. On the other hand, the pulleys do not manage to compensate for any such differences in the elastic characteristics of the bending members.

Moreover, the crossbows of known art usually take the form of a device which allows little or no possibility of adapting it to the requirements of the user: once a crossbow of known art has been built to certain specifications, the maximum power or the force required for the loading are substantially fixed and can no longer be varied, except with laborious replacements of components which, in any case, are beyond the common user's skill. These interventions, in fact, are dangerous and also void the warranty provided by the manufacturer.

The present disclosure, therefore, moves from the position of the technical problem of providing a device for launching a projectile or a launch object in general which makes it possible to overcome at least one of the drawbacks specified above with reference to the known art, and to gain further advantages.

As defined in independent claim 1, this is obtained by providing a device for launching a projectile or a launch object in general, comprising:

-   -   a stock having a longitudinal development direction between a         rear or proximal end and a front or distal end,     -   at least two bending members associated to said stock on         opposite sides of it and having a preferential development         direction, said bending members being apt to be subjected to         flexing in order to accumulate and supply energy usable to         launch said projectile, and released in a rest condition,     -   tensioning means of said bending members,     -   pushing means of said projectile apt to cooperate with said         bending members,

wherein said tensioning means comprise at least two cams arranged on opposite sides of the stock, each of which is pivoted at a respective first axis of rotation and is associated to at least one corresponding bending member, so that an angular displacement of a cam around said first axis of rotation determines a flexing action on said at least one corresponding bending member,

and said pushing means comprise at least two pushing arms arranged on opposite sides of the stock and connected to each other through a flexible pushing member for pushing said projectile,

wherein each of said pushing arms is pivoted at a respective axis of rotation and is apt to support a portion of said flexible pushing member, each of said pushing arms being operatively connected to a respective cam, so that a rotation of each pushing arm in a first rotation direction determines a flexing of said bending members by means of the respective cam during a loading phase of the device and that, during a launch phase of said projectile, a return of the bending members towards said rest condition determines, by means of the cam, a rotation in the opposite direction of each pushing arm,

wherein said device further comprises a flexible force member for commanding a rotation of a pushing arm during said loading phase, and two pairs of pulleys arranged on opposite sides of the stock, wherein each pair comprises a first pulley interposed between a respective pushing arm and said flexible pushing member, and a second pulley interposed between the respective pushing arm and said flexible force member, said first pulley being rotatably connected to said second pulley for a coordinated rotation thereof around respective axes of rotation, so that in said rest condition the flexible pushing member is partially wound on the first pulley, and that during said loading phase the flexible pushing member gets unwound from the first pulley and the flexible force member gets wound on the second pulley, and that during said launch phase the flexible pushing member gets wound on the first pulley and the flexible force member gets unwound from the second pulley.

Secondary characteristics of the subject of the present disclosure are defined in the corresponding dependent claims.

The subject of the present disclosure provides some significant advantages.

A main advantage lies in that the device permits a reduction in the stresses acting on the structure in the end-of-stroke arrest, thanks to the gradual absorption of the inertia and kinetic energy of the parts in movement in a braking run which follows the propulsive run. Furthermore this braking run is especially long as can be seen from the drawings. Also the braking run does not cut short the useful run of the limbs or bending members, for example by elastically intercepting the propulsive wire some distance before their neutral position as conceivable in devices of known art, that is, while they are still partially under tension; on the contrary, the braking run intervenes when the bending members have exhausted all the stored energy and when they have crossed the neutral, zero energy state while flexing in the opposite direction. The device can thus handle higher energies while also featuring smoother and more silent action, and higher safety levels for the user particularly in case of dry firing, compared to known-art devices.

A second advantage lies in that the device makes it possible to load higher energies compared to known-art devices. In fact the use of a solid body (i.e., said cams) as the primary mover acting on the bending members (rather than a wire) allows for the application of greater force and the use of more rigid bending members, thereby increasing the maximum energy that can be transmitted.

A third advantage is that the increment of the length of wire (i.e., of said flexible force member) to be wound on the force pulleys (i.e., said second pulleys), consequent chiefly to them being attached to levers (i.e., said pushing arms) and augmentable in various ways which will be shown, widens the scope for force-draw curve reshaping compared to known-art devices. In particular it is considered desirable to obtain a force-draw curve as flat as possible along most of its length so as to minimize the maximum effort that the user has to put in loading the device (commonly referred to as draw weight) in relation to the draw length and, since this last is essentially limited for devices of practical size, in relation to the energy stored.

A fourth advantage lies in that the device makes it possible to vary the specific use characteristics and it has a simpler maintenance. In fact said bending members are released in the rest condition, i.e. they do not present accumulated elastic energy and are non-deformed, so they can easily and safely be replaced with other bending members of same or different characteristics. Also the bending members do not present the risk of seeing their performance degraded in warmer storing conditions.

Another advantage lies in that said device makes it possible to synchronize the rotation of the left and right pushing means or pushing arms, in order to compensate for asymmetries in the elastic properties of left and right bending members. This determines a uniform distribution of the force acting on the projectile during the launch phase, eliminating the components of the acting force which are orthogonal to the launch direction, which benefits the launch accuracy.

A further advantage lies in that the device is of more limited lateral dimensions since the bending members are oriented substantially parallel to each other and to the stock and they lie close to it, while the externally protruding pushing arms need not extend much as the distance multiplication burden lies mostly with the pulleys.

In an embodiment, the pushing arms are rotatable between a first position of maximum loading and a second position of maximum discharge. Between said first and second positions, there is a neutral position at which the bending members do not present accumulated elastic energy. In particular, in said first position of maximum loading the pushing arms are rotated towards the proximal end of the stock, and in said second position of maximum discharge they are rotated towards the distal end of the stock.

To be more specific, said second position corresponds to the maximum advance of the pushing arms towards the distal end, in the braking stroke or run after the launch stroke, where with launch stroke it is meant the run of the pushing arms between said first position of maximum loading and said neutral position, while with braking stroke it is meant the run of the pushing arms between said neutral position and said second maximum discharge position.

Therefore, in the loaded device, the bending members are initially in a bent or flexed configuration; during the launch phase, the bending members gradually reduce the flexing, they pass the rest position (corresponding to said neutral position) and continue their movement by flexing in the opposite direction, until they get to a configuration of maximum counter-flexing corresponding to said second position of maximum discharge. One advantage of this solution is that it allows for a gradual and non-sudden stop of the components at the end of the launch phase, thereby reducing the stresses at the end of the stroke and the risk of damaging the device.

Contrast means, operating when the pushing arms are between the neutral position and the position of maximum discharge may also be optionally provided in order to cooperate with the bending members in slowing down the moving parts.

In addition or in alternative to the contrast means, the device may include auxiliary pushing means including at least one elastic member apt to accumulate energy during the loading phase and apt to supply energy to the pushing means during the launch phase. This makes it possible to increase the power of the device for a same overall dimensions.

In an embodiment, each pushing arm forms a single part with a respective cam and the axis of rotation of the pushing arm is the same as the axis of rotation of the respective cam. This solution has the particular advantage of requiring a lower number of parts and of being of simpler construction.

In an embodiment, each pushing arm is operatively connected to a respective cam using at least one connecting rod pivoted to the pushing arm and to the cam. This solution makes it possible to reduce the maximum lateral dimensions of the device and allows for greater design flexibility.

In an embodiment, the bending members are arranged so that their preferential development direction is substantially parallel to the longitudinal development direction of the stock. This benefits the compactness of the device, reducing the lateral dimensions. Preferably, the bending members are positioned close to the stock.

In an embodiment, the bending members, the cams and the pushing arms are arranged in a manner substantially symmetrical with respect to the stock. This configuration is advantageous as the symmetrical arrangement favors a symmetrical and balanced distribution of the forces acting on the stock and the elimination of the residual forces acting on the stock itself.

In an embodiment, the first axis of rotation of the cam moves together with a portion of at least one bending member, in a direction substantially orthogonal to the development direction of the bending member. More specifically, each cam is pivoted using a connection element comprising a first portion which is housed idle in a slot of the cam and at least one other portion which is associated to a tract of a corresponding bending member.

In an embodiment, at least one retaining member is provided on each side of the stock, hinged on it, with the purpose of holding a portion of said connection element so as to guide it and constrain it along its movement. In this case the pushing arm and said retaining member rotate in a coordinated fashion.

In an embodiment the device further comprises associating means, or supports, of said bending members to the stock; the associating means are apt to prevent a translation of a first tract of a bending member, for instance an end of it, in a direction orthogonal to the preferential development direction, and to allow said first tract a flexing movement, and/or an angular displacement with respect to the stock, and/or a translation in the preferential development direction of the bending member. To be more specific, said associating means are positioned at the two ends of a bending member.

In an embodiment, a first cam and a second cam opposite thereto are hinged on a pivot body associated to the stock and positioned between the opposing cams; the axis of the pivot body defines a second axis of rotation of said cams.

In an embodiment, a slide is positioned between one cam and the respective symmetrical cam, and comprises the pivot body; the slide can run along the device stock in a direction parallel to the longitudinal development direction of the stock. So, the movement of each cam is synchronized with that of the respective cam positioned symmetrically. This makes for a uniform pull on the propulsive flexible member.

In an embodiment each pushing arm supports a first pulley which holds one end of a propulsive flexible pushing member with the other end held by the symmetrically opposite pulley on the other side.

In an embodiment, one flexible force member is provided, having each end associated to a respective second pulley. In this embodiment, the rotation of the second pulleys in a winding direction causes the rotation of the pushing arms, which are being pulled by the flexible force member. The flexible force member passes from one side to the opposite side in a position suitable to maximize the length to be wound. More specifically the flexible force member is oriented in a direction approximately tangent to the path described by the respective pushing arm. This reduces the tension on the flexible force member and increases the eligible size of the second pulleys, increasing the scope for force-draw curve reshaping.

In an alternative embodiment, two flexible force members are provided, one on each side of the stock, each one having a first end associated to a respective second pulley and a second end associated to a side appendix, for instance a lateral arm, extending from a respective retaining member. In a preferred embodiment, the pushing arm and the corresponding lateral arm rotate in opposite directions moving one towards the other during loading and away from each other during launch. Therefore, by attaching one end of the flexible force member to the retaining member, the length that is to be wound around the second pulley is increased and the tension in the flexible force member is reduced, so that the flexible force member can be thinner. This allows greater design freedom for the second pulley, because it can now have a larger maximum radius and a smaller minimum one. Consequently, the eccentricity value of the second pulley can be selected in a larger interval. This is beneficial since a larger second pulley widens the scope for force-draw curve reshaping.

Moreover, in said embodiment, the retaining members cooperate with the pushing arms in transmitting energy to and from the bending members. Therefore, the overall pushing action is more balanced and a better structural efficiency is achieved. For instance, the pushing arms can be lighter, because they are subjected to a lower stress.

In an embodiment, the first pulley and the second pulley on the same pushing arm are associated to a same common pivot rotating jointly with them. Therefore the first and the second pulleys have the same axis of rotation and the same angular velocity. The direction of rotation of a pair of pulleys may be either coherent with the respective pushing arm (for instance, both clockwise, or both counterclockwise), or opposite to the respective pushing arm (one clockwise and the other counterclockwise), depending on which side of the pulleys the flexible members are fastened to. The rotation of the pulleys may perform a plurality of turns or revolutions.

In an alternative embodiment, the first pulley and the second pulley are pivoted at different axes of rotation; in fact each pulley is jointly associated to a respective pivot, which is rotatably associated to the pushing arm. The two pulleys are operatively connected by means of a gearing for example with toothed portions or frictionally coupled. This allows to reduce the overall dimensions of the pulleys, to increase the draw length (useful in particular when applied to a catapult), to widen design freedom for obtaining the desired characteristics of the device.

Further advantages, characteristics and the modes of employment of the subject of the present disclosure will become apparent from the following detailed descriptions of preferred embodiments thereof, presented for exemplificative and not limitative purposes.

It is however evident that each embodiment described in this disclosure may present one or more of the advantages listed above; in any case, it is not required that each embodiment presents at the same time all the advantages listed.

Reference will be made to the figures of the attached drawings, in which:

FIG. 1 shows a plan view of an embodiment of a crossbow according to the known art;

FIG. 2A shows a perspective view of a first embodiment of a device for launching a projectile according to the present disclosure, in a first operative position;

FIG. 2B shows a perspective view of the device in FIG. 2A, in a second operative position;

FIG. 2C shows a perspective view of the device in FIG. 2A, in a third operative position;

FIG. 3 shows a perspective view of an enlarged detail of the device in FIG. 2A, from which some components were removed;

FIG. 4 shows an exploded perspective view of a further enlarged detail of the device in FIG. 2A;

FIG. 5 shows an enlarged front perspective view of the device in FIG. 2A;

FIG. 6 shows an exploded perspective view of a further enlarged detail of the device in FIG. 2A;

FIG. 7 shows an enlarged side perspective view of the device in FIG. 2A;

FIG. 8 shows a perspective view of a further enlarged detail of the device in FIG. 2A, from which some components were removed;

FIG. 9 shows an exploded perspective view of a further enlarged detail of the device in FIG. 2A;

FIG. 10 shows a perspective view of a further enlarged detail of the device in FIG. 2A;

FIG. 11 shows an exploded perspective view of the detail in FIG. 10;

FIG. 12 shows a perspective view of the device in FIG. 2A, in a non-operative position;

FIG. 13 shows a perspective view of the detail of FIG. 10, in a non-operative position;

FIG. 14A shows a perspective view of a second embodiment of a device for launching a projectile according to the present disclosure, in a first operative position;

FIG. 14B shows a perspective view of the device in FIG. 14A, in a second operative position;

FIG. 14C shows a perspective view of the device in FIG. 14A, in a third operative position;

FIG. 15 shows a perspective view of an enlarged detail of the device in FIG. 14A, from which some components were removed;

FIG. 16 shows an exploded perspective view of a further enlarged detail of the device in FIG. 14A;

FIG. 17 shows a perspective view of a third embodiment of a device for launching a projectile according to the present disclosure, in a first operative position;

FIG. 18 shows an exploded perspective view of a further enlarged detail of the device in FIG. 17;

FIG. 19 shows a perspective view of an enlarged detail of a fourth embodiment of a device for launching a projectile according to the present disclosure, in a first operative position.

An embodiment of an archery crossbow 1001 according to the known art (U.S. Pat. No. 6,155,243) is shown in FIG. 1. The crossbow 1001 has a stock 1002 with a butt 1003, two flexing or bending members 1010 (or limbs) connected to said stock 1002, a propulsive wire 1031 for pushing a projectile, a fasten and release system (not shown, but located near the butt 1003) for holding and releasing said propulsive wire 1031 in a launch position, a shooting trigger (not shown). The free ends of the bending members 1010 support eccentric pulleys 1009, so that the propulsive wire 1031 passes at these and connects each pulley to the opposite bending member. During the loading phase, shown in FIG. 1, the propulsive wire 1031 is drawn towards the butt 1003, causing the eccentric rotation of the pulleys 1009, the flexing of the bending members 1010 and the accumulation of elastic energy in these. During the launch phase, the same movements take place in the opposite direction, with the transfer of energy to a projectile (not shown) which slides in a suitable guide track 1008. This type of known-art crossbow 1001 has the disadvantages already mentioned above.

A first embodiment of a device for launching a projectile, an arrow, a bolt, or a launch object in general, made according to the present disclosure, is shown in FIGS. 2A to 13, where it is indicated with the reference number 1.

Hereinafter, the present description will refer in particular to archery crossbows; anyway, the same inventive principles of the present disclosure can be similarly applied to other launching devices, such as for example a bow or a catapult.

The crossbow 1 comprises a stock 2 with a longitudinal development direction 201, comprised between a rear or proximal end 205 and a front or distal end 206. The other components of the crossbow 1 are associated to the stock 2. The portion of the stock 2 which is closest to a user during use, that is, the rear or proximal end 205, comprises, in fact, a butt 3, a handle 4, a fastening system 6 for reversibly fastening a flexible pushing member 31 for pushing a projectile, a trigger 7 which makes it possible to open the fastening system 6 in order to release the flexible pushing member 31 when launching the projectile. The components listed so far can be considered to be substantially known-art components and, therefore, will not be described in greater detail.

FIGS. 2A, 2B and 2C illustrate the crossbow 1 in three different operative positions, which are respectively a neutral (rest) condition, a loaded condition, and a maximum discharge condition.

The crossbow 1 comprises at least two bending members 10, or flexing members, which have an elongated shape along a preferential development direction 202. For example, the bending members 10 have a parallelepiped-like shape. They may be made of wood, metal, fiberglass, plastic or composite material, e.g. including glass or carbon fiber, or other suitable material.

The bending members 10 are suitable for being subjected to bending or flexing in order to accumulate the elastic energy required to launch the projectile, and to subsequently supply said energy to the projectile during the launch. At the end of the launch of the projectile, the bending members 10 are released in a rest condition, in which they do not present accumulated elastic energy and are non-deformed.

In the embodiment represented here, the bending members 10 are positioned substantially adjacent to the stock 2 and in a symmetrical manner with respect to it; in the example, their preferential development direction 202 is substantially parallel to the longitudinal development direction 201 of the stock 2. To be more specific, there are four bending members 10, as there are two bending members 10 on each side of the stock 2.

The bending members 10 are associated to the stock 2 on opposite sides of it. To be more specific, each bending member 10 is associated to the stock 2 through associating means positioned near the proximal end 101 and the distal end 102 of the bending member 10.

The associating means comprise supports 11, each of them comprising in turn a first sidebar 14 and a second sidebar 15 parallel therebetween; for instance, the sidebars 14, 15 are cylindrical stems. The sidebars 14, 15 are pivotably mounted on a small elongated plate 16 orthogonal to the sidebars 14, 15. In the example, two elongated plates 16 parallel therebetween are provided for each support 11.

Moreover, the first sidebar 14, i.e. the sidebar closer to the stock 2, and the elongated plates 16 are pivotably mounted on a first flat protrusion 17 laterally extending from the stock 2, to which the first protrusion 17 is firmly joined or integral.

The first and second sidebars 14, 15 are kept in a spaced relation by the elongated plates 16, in order to define a housing for a respective end 101, 102 of a bending member 10.

In fact they touch opposite sides of the bending member 10, and in particular of said ends 101, 102, which are held between the respective sidebars 14, 15. The first sidebar 14 is positioned at the inner side of the bending member 10 with respect to the stock 2 and the second sidebar 15 is at the outside of the bending member 10.

Moreover, said ends 101, 102 are slightly jutting out in the development direction 202 with respect to the sidebars 14, 15.

The first sidebar 14 also acts as a spacer, in order to keep the bending member 10 slightly displaced from the stock 2.

Since the elongated plates 16 are rotatable about an axis 18 with respect to the first protrusion 17, the whole support 11 can rotate about the same axis 18 following a flexing movement of the bending member 10. That is, the support 11 rotates following the movement of the respective end 101, 102 of the bending member 10 when the latter, flexing, varies its angle with respect to the stock 2; in other words, a partial rotation of said end 101, 102 is permitted.

Therefore, the bending member 10 can assume a simply curved or arched shape, without being hampered by the supports 11 in said flexing movement, thereby preventing the creation of longitudinal stresses in the bending member 10.

Moreover, the sidebars 14, 15 have a curved profile (in the example, a cylindrical profile) and are rotatable about the respective longitudinal axes. Therefore, a translation movement of the bending member 10 along its preferential development direction 202 is at least partially allowed, when required. In this case the sidebars 14, 15 rotate during said translational movement, thus reducing the mutual friction between the bending member 10 and the sidebars 14, 15. A thin plate 19, for instance a metal plate, can be locally interposed between the bending member 10 and each respective sidebar 14, 15 in order to further reduce friction and avoid wear of the bending member 10.

In other words, the associating means, in particular the supports 11, are apt to prevent a side translation of a respective tract of a bending member 10, i.e. a translation along a direction 203 perpendicular to its preferential development direction 202, whereas it allows said tract an angular displacement or a flexing movement, and a longitudinal translation along development direction 202. To be more specific, said associating means are arranged at the proximal end 101 and at the distal end 102 of the bending member 10.

As a consequence, the described embodiment, as well as permitting the connection of the bending members 10 to the stock 2, allows the bending members 10 to easily flex towards the stock 2 during a loading phase of the device 1, and to counter-flex towards the outside in a stroke towards the maximum discharge position.

However, in alternative embodiments the bending members 10 might be associated to the stock 2 in different manners.

For instance, the bending members 10 can be secured using a flexible element surrounding one bending member 10 and the one on the opposite side.

For instance, in an alternative embodiment, the bending members 10 are associated to the stock 2 by means of supports comprising only a first sidebar 14 and lacking said second sidebar 15. Each end 101, 102 of the bending members 10 is held against a respective first sidebar 14 through a wire or flexible holding means (for instance, a hook-and-loop fastener), which envelops the end 101, 102 itself and the first sidebar 14, or attaches the end 101, 102 itself to said sidebar 14, or envelops the end 101, 102 itself and the corresponding end 101, 102 of the bending member 10 on the opposite side of the stock 2.

As a further alternative, at least one tract of a bending member 10 is constrained with a rigid joint to the stock 2, that is, said tract is tightly joined to the stock 2 so as to substantially prevent any movement (translation, rotation and/or flexion movement) of the tract itself with respect to the stock 2. In other words, in said further alternative the associating means are apt to join a tract of a bending member 10 to the stock 2 in such a way as to prevent said tract from translating, with respect to the stock 2, along said preferential development direction 202 and along a direction 203 orthogonal to said preferential development direction 202, and from performing an angular displacement with respect to the stock 2.

A combination of these methods, or of other methods, might also be possible; moreover, different bending members 10 might be associated through different methods.

The crossbow 1 comprises also at least two retaining members or lever 21, arranged on opposite sides of the stock 2, symmetrical with respect to said stock 2. Each retaining member 21 is pivoted at a respective axis of rotation 22 and is associated to a portion of at least one bending member 10 through a connection element 27. The retaining member 21 retains the connection element 27 and guides it during all phases of operation of crossbow 1, and moreover determines the position and the displacement of fulcra of respective tensioning means during said phases.

In the example, four retaining members 21 are provided, i.e. two retaining members 21 on each side of the stock 2. Each retaining member 21 is associated to a respective portion of the connection element 27, said portion being situated at the same height as one respective bending member 10.

Each pair of retaining members 21 is pivotably mounted, at first ends 211, on a pin 24 top-and-bottom extending from a second flat protrusion 23 laterally extending from the stock 2. Said axis of rotation 22 corresponds to a longitudinal axis of said pin 24, which is housed in seats or through holes 215 in said first ends 211 of the retaining members 21.

To be more specific, the second protrusion 23 is sufficiently long to laterally stick out of the bending members 10 on the same side and it is sandwiched between the first ends 211 of the respective pair of retaining members 21.

A second end 212 of each retaining member 21 is associated to a portion of connection element 27, in particular to a connection member 28, and to the respective bending member 10. Said second end 212 comprises a “C”-shaped housing 213 opened towards the bending member 10. A connection element 27, for connecting a retaining member 21 to a bending member 10, comprises two substantially semi-cylindrical connection members 28 and a cylindrical collar 29 interposed between the semi-cylindrical connection members 28 in aligned arrangement, i.e. two semi-cylindrical connection members 28 are positioned symmetrically with respect to a plane and are connected to each other by said cylindrical collar 29.

The curved surface of the semi-cylindrical member 28 has radial grooves 281, by means of which the semi-cylindrical connection member 28 is interlocked with a respective second end 212 of a retaining member 21. When the semi-cylindrical member 28 and the retaining member 21 are clamped together, the semi-cylindrical member 28 can rotate inside the “C”-shaped housing 213, due to the shape of the groove 281 and the corresponding profile of the housing 213, so as to allow the retaining member 21 to vary its angle with respect to the bending member 10 and to connection element 27.

A flat surface of the semi-cylindrical connection member 28, which faces the bending member 10, has a dovetail joint 282 for joining to a corresponding element 108 attached to a tract of the bending member 10, preferably at a region positioned about half way along its length. Thus, each semi-cylindrical connection member 28 is apt to move a portion of a respective bending member 10.

Therefore, the retaining member 21 is anchored to the respective bending member 10 by means of said connection member 28. Consequently, a flexing action on a bending member 10 determines an angular displacement of the corresponding retaining member 21 around its axis of rotation 22. On the other hand, the retaining member 21 keeps the respective bending member 10 in position inside the supports 11 and prevents an overall translation of the whole bending member 10 along its development direction 202.

Since it comprises two semi-cylindrical connection members 28, the connection element 27 is apt to be associated with two bending members 10.

The crossbow 1 further comprises tensioning means of the bending members 10, that is, means apt to bring the bending members 10 to a flexed position during a loading phase, and pushing means 30 of said projectile, apt to cooperate with the bending members 10 to transfer energy to the projectile to be launched.

The pushing means include a flexible pushing member 31, such as, for example, a propulsive wire for pushing a projectile, and at least two lever arms or pushing arms 32 positioned on opposite sides of the stock 2 and connected to each other by the flexible pushing member 31.

In the example, two pushing arms 32 are provided, which laterally extend from the stock 2 and pass in between the bending members 10 on the same side. Each pushing arm 32 is pivoted at a respective first axis of rotation 33.

In the embodiment illustrated, the overall structure is such that each side of the stock 2 has two bending members 10 opposite to each other with respect to a plane on which the pushing arms 32, and in particular cam sections 323, lie and on which their rotation movement takes place, in order to create, overall, a group of four bending members 10 symmetrical with respect to the longitudinal development direction 201 of the stock 2.

To be more specific, the pushing arm 32 has a slot 35, in which the cylindrical collar 29 of a respective connection element 27 is positioned idle. Therefore, the pushing arm 32 is pivoted at the connection element 27 and its axis of rotation 33 substantially corresponds to a longitudinal axis of said cylindrical collar 29. To be more specific, the slot 35 is a hole.

Moreover, the pushing arms 32 are hinged each other, in particular first ends 321 of the pushing arms 32 are pivoted on a pivot body 82. The pivot body 82 is slidingly associated to the stock 2 in order to run parallel to said longitudinal development direction 201 along a guide track or rail 84, which for instance is joined to the stock 2 and positioned parallel to the longitudinal development direction 201.

During rotation of the pushing arms 32 around said first axes of rotation 33, the pushing arms 32 rotate also around a second determined axis 83, corresponding with an axis of the pivot body 82; the second axis of rotation 83, which preferably is orthogonal to the longitudinal development direction 201, moves with the pivot body 82 along the guide rail 84.

A section 323 of the pushing arm 32, comprised between the first end 321 and the slot 35, behaves like a cam, i.e. transforms an angular displacement into a linear displacement. That is, since the pivot body 82 is constrained to the guide rail 84 and cannot move towards a side of the stock 2 perpendicularly to the longitudinal direction 201, a rotation of the cam section 323 about said first axis of rotation 33 entails also a translation of the slot 35, and of the connection element 27 housed therein, along a direction 203 substantially perpendicular to the longitudinal direction 201, and vice versa. More specifically the axis of rotation 33 moves along an arched path determined by the retaining members 21.

Therefore, the cam sections, or cams, 323 are comprised in the tensioning means of the bending members 10, i.e. they are apt to deform the bending members 10 by means of a rotation movement. To be more specific, the tensioning means comprise at least two cams 323 positioned at opposite sides of the stock 2, symmetrical with respect to said stock 2. Each cam 323 is pivoted at a respective first axis of rotation 33 and is associated to at least one corresponding bending member 10. In particular, the connection elements 27 connect the cams 323 to the bending members 10.

In other words, thanks to the connection element 27 and the pivoting methods, a portion of each bending member 10 is associated idle to the respective slot 35 so as to allow said portion of bending member 10 to make a translation movement together with the slot 35; then the first axis of rotation 33 makes translation movements together with a portion of the respective bending members 10. In particular, said translation movement substantially takes place in the direction 203 orthogonal to the preferential development direction 202 of the bending member 10 and is constrained on an arched path determined by the rotation of the retaining members 21 around axes 22.

That is, an angular displacement of the pushing arms 32, and in particular a rotation movement of said cam sections 323 around said first axes of rotation 33, creates a flexing action on the corresponding one or more bending members 10, causing a flex variation of the bending members 10 themselves, and a rotation movement of the retaining members 21. Vice versa, a flex variation of the bending members 10 creates a rotating action on the corresponding pushing arms 32 and retaining members 21.

The rotation of the pushing arms 32 in a first rotation direction determines, by means of the cams 323 and the connection elements 27, a rotation of the retaining members 21 and a flexing of the bending members 10 during a loading phase of the crossbow 1; during a launch phase of said projectile, a return of the bending members 10 towards said rest condition determines, by means of the cams 323 and the connection elements 27, a rotation in the opposite direction of the pushing arms 32.

In other words, the pushing arms 32, during a rotation movement, are apt to cooperate with the tensioning means, i.e. the cams 323, to realize a transfer of energy to said bending members 10 during the loading phase of the crossbow 1, and a transfer of energy from said bending members 10 to said pushing means 30 during the projectile launch phase.

To be more specific, in the present embodiment said first rotation direction during the loading phase is directed towards said proximal end 205 of the stock 2, and said rotation in the opposite direction during the launch phase is directed towards said distal end 206 of the stock 2.

In the present embodiment, each pushing arm 32 forms a single part with a respective cam 323; in this case, the axes of rotation 33 of the cam 323 and of the respective pushing arm 32 are the same.

As illustrated in FIG. 2B, the pushing arms 32 can be rotated between a first maximum loading position, with pushing arms 32 rotated towards the proximal end 205 of the stock 2 and corresponding to a maximum flexing of the bending members 10, and, as illustrated in FIG. 2C, a second maximum discharge position following the launch of the projectile, with pushing arms 32 rotated towards the distal end 206 of the stock 2 and corresponding to a maximum counter-flexing of the bending members 10. Between said first and second positions, there is a neutral position, at which the bending members 10 do not have accumulated elastic energy, as they are in a rest condition in a non-deformed state, as illustrated in FIG. 2A.

To be more specific, in the present embodiment the bending members 10 flex towards the stock 2 during the loading phase and counter-flex towards the outside in the launch phase: this is due to the position of the second axis of rotation 83 with respect to the plane on which the first axes of rotation 33 lie, in relation to the rotation movement described by the cams 323. In other words, in the neutral position the second axis of rotation 83 is between the distal end 206 and said plane of the first axes of rotation 33.

It is evident, in any case, that an opposite flexing method for the bending members 10 may also be used. In fact, a flexing method away from or closing to the stock 2 during the loading phase may be selected through an opportune dimensioning and assembly of the cams 323 and pushing arms 32, and is substantially unrelated to the other specific characteristics of the embodiments described.

A second end 322 of the pushing arm 32 supports a pair of pulleys 145, 146 rotatably associated to it. Therefore, two pairs of pulley 145, 146 are provided, arranged on opposite sides of the stock 2, each pair being associated to a respective pushing arm 32.

In the example, the pulleys 145, 146 are positioned at opposite side of the second end 322, i.e. a first pulley 145 is at top side of the pushing arm 32 and a second pulley 146 is at bottom side of the pushing arm 32.

The first and second pulleys 145, 146 associated to a same pushing arm 32 are rotatably connected for a coordinated rotation around an axis of rotation 150. To be more specific, the first and second pulleys 145, 146 rotate jointly, since they are associated or fastened to a same common pivot 147 rotating jointly with them. The pivot 147 extends orthogonal to the surface of the pulleys themselves. The pivot 147 is housed idle in a slot, or in a through hole, 36 provided in the second end 322 of the pushing arm 32 and can rotate in this hole 36 with respect to the axis 150. The axis 150 makes translation movements together with the second end 322 of the respective pushing arm 32.

Preferably, the pulleys 145, 146 lie on planes which are parallel to each other, and in particular are parallel to the longitudinal direction 201 and to the plane on which the pushing arms 32 move.

In the present disclosure, the term “pulley” should be generally understood as a rotatable member having a profile or a side edge, or a part of profile, apt to wind at least partially a flexible member during a rotation movement, or apt to house a portion of a flexible member passing around it; in any case, it is not required that the side edge or profile of a pulley define a closed line; in fact, the figures show a pulley 145 which has an interrupted side edge.

A side edge, or profile, of the first pulley 145 has a track or groove 1451 in which one end 311 of the flexible pushing member 31 is supported and/or secured and in which the flexible pushing member 31 itself winds. In other words, the first pulley 145 is interposed between the pushing arm 32 and the flexible pushing member 31.

The first pulley 145 has an eccentric side edge with respect to the longitudinal axis 150 of the pivot 147; the first pulley 145 has a very pronounced eccentricity: in fact, it has a substantially elliptical profile, wherein the pivot 147 is positioned close to the side edge at the major axis of the ellipse.

The flexible pushing member 31 connects the pushing arms 32 to each other; to be more specific, it connects the first pulley 145 a of one pushing arm 32 a to the first pulley 145 b of the other pushing arm 32 b, and, in said the rest condition, it is partially wound on said first pulleys 145.

The crossbow 1 comprises a flexible force member 37, such as for example a wire, which commands or forces the rotation movements of the pushing arms 32.

Each of first lengths, in particular ends 371 a, 371 b, of the flexible force member 37 is secured in a track or groove 1461 of a side edge of a respective second pulley 146, in which the flexible force member 37 itself winds. In other words, the second pulley 146 is interposed between the pushing arm 32 and the flexible force member 37.

Also the second pulley 146 has an eccentric side edge with respect to the longitudinal axis 150 of the pivot 147, even though in the example the second pulley 146 is less eccentric than the first pulley 145.

A second length or intermediate region 372 of the flexible force member 37 goes round a tightener element, for instance a frame 61, associated to the stock 2; to be more specific, said intermediate region 372 is housed in a track or groove 611 of a side edge of said frame 61.

Also the flexible force member 37 connects the pushing arms 32 to each other. To be more specific, it connects the second pulley 146 a of one pushing arm 32 a to the second pulley 146 b of the other pushing arm 32 b; moreover, in said rest condition, the flexible force member 37 is partially wound on said second pulleys 146 and rounds said frame 61.

The flexible members 31, 37 are secured to the respective pulleys 145, 146 in such a way that, during an angular displacement of a pair of pulleys 145, 146 around the axis of rotation 150, the unwinding of the flexible pushing member 31 from the first pulley 145 is accompanied by the winding of the flexible force member 37 on the second pulley 146, and vice versa.

The frame 61 is associated and secured to the stock 2 in a lockable slide arrangement, for instance by means of a socket 62 fastened to the frame 61 and cooperating with a proper counterpart element 63 attached to the stock 2. Moreover, the cooperation between the socket 62 and the counterpart element 63, for instance through a dove-tail joint, is such as to allow a sliding movement of the frame 61 along the stock 2 and its longitudinal development direction 201.

A locking lever 64 is pivoted to the stock 2, at a pivot 65 integral with a side of the stock 2 and housed in a first seat 641 of the lever 64. A connecting rod 66 is pivoted to the socket 62 at a pin 621 and to the locking lever 64 at a second seat 642. The second seat 642 is surrounded by a “L”-shaped slot 643 for an end of the connecting rod 66.

When the locking lever 64 is rotated towards a locking position shown in FIG. 10, the frame 61 is pressed towards the proximal end 205 of the stock 2 and the flexible force member 37 is tightened. When the second seat 642 is above a line connecting the first seat 641 and the pin 621, the frame 61 is locked: in fact, the force exerted by the flexible force member 37 on the frame 61 is transmitted to the locking lever 64 by the connecting rod 66 and the resulting torque is in the opposite direction of an unlocking rotation of the locking lever 64.

When the flexible force member 37 is to be loosened by a user, the locking lever 64 is rotated in the unlocking direction shown in FIG. 13. Consequently, the second seat 642 goes below the line connecting the first seat 641 and the pin 621; after this point, the frame 61 is moved towards the distal end 206 of the stock 2 and the flexible force member 37 is loosened, as shown in FIG. 12 for a non-operative position of the crossbow 1.

Contrast means 50, associated to the stock 2 and operatively connected to the pushing arms 32, and in particular to cams 323, may also in case be provided in order to dampen the motion of the pushing arms 32. Depending on the extent of the counter-flexing permitted for the bending members 10 (also related to their rigidity) and the choices for the dimensioning of the components of the crossbow 1, the contrast means 50 may also dampen the motion of the bending members 10 by means of the interaction with the cam sections 323 of the pushing arms 32.

Said contrast means 50, for example, include an end wall 51 from which a hollow cylinder 52 protrudes along the longitudinal direction 201, a spring 53, a thrusting member 54 for said spring 53.

The spring 53 is positioned around the hollow cylinder 52 and against the end wall 51. The thrusting member 54 has a thrusting wall 541 apt to thrust or compress the spring 53 against the end wall 51. A rod 55 protrudes from the thrusting wall 541 and is apt to slide inside a bore 521 of the hollow cylinder 52, as a guide for a translation movement of the thrusting member 54 along said longitudinal direction 201.

The thrusting member 54 is associated to a slide 25, to which the pivot body 82 is connected. The slide 25, which is associated to the stock 2 and positioned between the cams 323, is apt to move parallel to the longitudinal development direction 201 along the guide rail 84. In the example, the slide 25 has a dove-tail housing 251 apt to slidingly receive the guide rail 84.

The contrast means 50 are arranged so as to apply a force against the cam sections 323 when the pushing arms 32 are beyond said neutral position towards said second maximum discharge position. In fact, when the pushing arms 32 have passed the neutral position, the thrusting wall 541 is in touch with the spring 53 and pushes against it. This way, the thrusting member 54 compresses the spring 53 and a slowing down of the motion of the pushing arms 32 is obtained thanks to the transfer of energy to the spring 53.

When the pushing arms 32 are between said first maximum loading position and said neutral position, the thrusting wall 541 is not in contact with the spring 53 and, therefore, the contrast means 50 do not have any influence on the motion of the pushing arms 32 themselves.

These same elastic means represented by the spring 53 cooperating with the thrusting member 54 can bring the pushing arms 32 back towards the neutral position, so that at the end of the launch phase they are in the neutral position again.

In an alternative embodiment, contrast means are not present and the entire effort of braking the parts in movement and recovering the neutral position is charged on the bending members in their counter-flexing motion and subsequent regaining of their neutral position.

Before a projectile is launched, the crossbow 1 is initially in the neutral condition (FIG. 2A), wherein the bending members 10 are in a rest condition and the flexible pushing member 31 is partially wound on the first pulleys 145 and extending between them.

During a loading phase of the crossbow 1, the user pulls the flexible pushing member 31 towards the proximal end 205 of the stock 2, until the flexible pushing member 31 is engaged in the fastening system 6. During this operation, the flexible pushing member 31 is progressively unwound from the first pulley 145 on each side and, due to the corresponding rotation of the first pulleys 145 and second pulleys 146 around the axes 150, the flexible force member 37 is progressively wound on the second pulley 146 on each side.

As a consequence, the flexible force member 37 forces both pushing arms 32 to rotate, in an initial direction, towards the proximal end 205 of the stock 2 around the respective first axes of rotation 33, and also around the second axis of rotation 83. That is, the flexible force member 37 commands the rotation of the pushing arms 32.

The rotation of the pulleys 145, 146 around the respective axis of rotation 150, that is, around the translating axis 150 of the pivot 147, is, therefore, coordinated with a respective pushing arm 32 (and a respective cam section 323) for a synchronized rotation of the pushing arm 32 itself (and of the cam section 323) around the respective first axis of rotation 33. In other words, the pulleys 145, 146 move synchronized with the respective pushing arm 32, with a combined translation and rotation movement.

Since the connection elements 27 are constrained by the retaining members 21, said rotation of the pushing arms 32 entails that the pivot body 82 and the second axis of rotation 83 translate towards the distal end 206 and the connection elements 27 translate towards the stock 2, almost perpendicularly to the longitudinal direction 201, accompanied by the rotation of the retaining members 21 around the respective axes 22.

As a consequence, the bending members 10 flex towards the stock 2 and accumulate elastic energy proportional to their flexing. A rotation of the ends 101, 102 of the bending members 10 with respect to the stock 2 is allowed by the supports 11 rotatable around axes 18, and a limited translation of the ends 101, 102 of the bending members 10 with respect to the supports 11 is allowed by the rotatably mounted sidebars 14, 15.

When the maximum loading position, corresponding to a maximum flexing of the bending members 10, is reached, the bending members 10 are in the bent configuration illustrated in FIG. 2B; moreover, the flexible pushing member 31 is at its maximum unwinding from the first pulleys 145 and the flexible force member 37 is at its maximum winding on the first pulleys 146. A projectile (not shown) can be placed in a suitable track 8 on the stock 2 and the crossbow 1 is ready for launching.

Pulling of the trigger 7 releases the flexible pushing member 31, and starts a projectile launch phase. The bending members 10 tend to return to the rest position, that is, the non-deformed neutral position, and therefore push the cam sections 323 towards the outside, almost perpendicularly to the longitudinal direction 201. The movement of the bending members 10 is constrained and accompanied by the rotation of the retaining members 21 around the respective axes 22.

Since the cam sections 323 are pivoted on the pivot body 82, the result of the pushing action of the bending members 10 on the cam sections 323 is that the cam sections 323 rotate in the opposite direction with respect to the loading phase. That is, the pushing arms 32 rotate too, towards the distal end 206 of the stock 2, and the pivot body 82 moves toward the proximal end 205.

During this movement, the flexible force member 37 exerts a torque on the second pulleys 146, which is transmitted to the first pulleys 145. Said pulleys 145, 146 rotate in an opposite direction with respect to the loading phase. The flexible force member 37 is progressively unwound from the second pulleys 146 and the flexible pushing member 31 is progressively wound on the first pulleys 145. In other words, the combination of the translation motion of the ends 322 of the pushing arms 32 with the rotation motion of the first pulleys 145 draws the flexible pushing member 31 and also winds it in the grooves 1451 of the first pulleys 145. Therefore, the pushing arms 32 pull the flexible pushing member 31 along the projectile track 8 and energy is transferred to the projectile by the push of the flexible pushing member 31 against it.

When the neutral position is reached, due to the inertia of the moving parts, i.e. the pushing arms 32, the retaining members 21, the pulleys 145, 146, and the bending members 10, said moving parts pass the neutral position and continue their run beyond the neutral position, tending towards the maximum discharge position, shown in FIG. 2C.

In this portion of the stroke, between the neutral position and the maximum discharge position, the bending members 10 are in a flexed position towards the outside of the stock 2 (that is, in a counter-flexed configuration with respect to the loaded position). Moreover, the flexible pushing member 31 is further wound on the first pulleys 145 with respect to the neutral position; the flexible force member 37 is further unwound from the second pulleys 146.

In case of an especially high residual kinetic energy (for example, in case of a very light projectile or of dry firing), the pushing arms 32 may reach said maximum discharge position, in which they are rotated towards the distal end 206 of a maximum angle with respect to the neutral position. In this position, the bending members 10 have a maximum flexing towards the outside of the stock 2. Moreover, there is the maximum winding of the flexible pushing member 31 on the first pulleys 145, which are almost in contact with each other, and the maximum unwinding of the flexible force member 37 from the second pulleys 146. As the axes 150 move forward and towards the stock 2, the second pulleys 146 give length of flexible force member 37 to second the movement of the pushing arms 32 and the first pulleys 145 take any length of propulsive flexible pushing member 31 that is made available, so that the rotation of the pulleys 145, 146 is not impeded and at the same time no flexible members 31, 37 goes slack. This is in particular obtained through a proper design of the side edges and profiles of the pulleys 145, 146.

Additionally, in this portion of the stroke the movement of the pushing arms 32 is opposed by the contrast means 50 (if they are present), which slow down the pushing arms 32 and also dissipate part of the kinetic energy; according to the methods described, these contrast means 50 only operate starting from the neutral position towards the maximum discharge position.

Thanks to the combined action of the bending members 10 and the spring 53, which tend to return to the respective non-deformed conditions, the entire system is then brought back to the neutral position, where it stops.

From the above description it is understood how the end-of-stroke shock is substantially eliminated, because the stop of the components at the end of the useful run is not sudden as with the known art, but takes place within the stroke between the neutral position and the discharge position, and return. This enables a greater reduction in the structural stresses, in the noise and in the risks related to the use of too light a projectile or no projectile at all. It also implies an overall smoother operation and it removes any apprehension or discomfort, psychological or physical, which may accompany the use of known-art devices, especially the more powerful ones in combination with lighter arrows.

The synchronization of the motion of the pushing arms 32 one with the other guarantees a balanced pull on the flexible pushing member 31 and this absolves a necessary condition for accuracy.

The use of solid levers as the primary mover, i.e. of cams 323 as tensioning means, acting on the bending members 10 allows for higher forces and therefore permits the use of more rigid bending members 10 compared to known-art devices. This allows the device to handle more energy and it also makes it possible to considerably increase (with respect to the known art) the ratio between the draw length and the extent of the shifting of the masses of the bending members 10, thereby increasing the efficiency of the conversion between potential and kinetic energy.

An adequate profiling of the cam sections 323 and of the pulleys 145, 146 also makes it possible to obtain a more extensive force-draw curve reshaping than in known-art devices. In particular it enables a more marked reduction in the maximum loading effort. The use of first pulleys 145 rotating with respect to the pushing arms 32 allows for greater design freedom in order to obtain the desired force-draw curve. In fact, the shape of this curve may be adapted to the desired requirements by envisaging an opportune profile and rotation angle for the pulleys. The more deformed the bending members 10 are, the more force is required for a further deformation of them, i.e. the higher is the required torque acting on the cam sections 323 and on the pushing arms 32 due to the force exerted by the flexible force member 37. In other words, the torque acting on the second pulleys 146 should increase during the loading phase. This is achievable by providing an eccentric side edge for the first pulleys 145: in this case the lever arm, with respect to axis 150, for the force exerted by the flexible pushing member 31 increases during the loading phase, and then an increasing torque on the second pulleys 146 is obtainable through an approximately constant force exerted by the user on the flexible pushing member 31.

Advantageously, as shown in FIG. 7, the distance D1 between a plane on which the first pulleys 145 lie and a plane on which the first ends 321 of the pushing arms 32, pivoted on the pivot body 82, lie is greater than the distance D2 between a plane on which the second pulleys 146 lie and said lying plane of the first ends 321.

Since the force transmitted by the flexible force member 37 to each pushing arm 32 is greater than the force transmitted by the flexible pushing member 31 to the same pushing arm 32, the difference between said distances D1 and D2 allows to compensate for the difference between said forces; that is, it allows to reduce or cancel out the torque acting on the pushing arm 32 on a plane perpendicular to the rotation plane of the pushing arm 32 itself.

It is also possible to modify the characteristics of the crossbow 1, adapting them to the use requirements, by replacing the bending members 10 with other bending members of different elastic characteristics, so as to have a different level of stored energy.

Note that the possibility of easily taking apart the crossbow 1 and replacing its components is linked to the fact that, in the neutral position, there are no members or components in elastic tension; therefore, the taking apart and the assembly do not require either special tools (e.g. presses) or special caution on the part of the user. In fact, the crossbow 1 can be easily and safely disassembled.

Further, in the launch phase the rotation movement of the first pulleys 145 towards the longitudinal axis 201 of the stock 2 makes it possible to substantially cancel out the inertia of the pulleys 145 with respect to the stock 2 and, therefore, the structure of the crossbow 1 and the user are subject to lower stresses.

Several variants of the described embodiment are possible.

There may also be auxiliary pushing means (not shown) in order to further increase the maximum power of the crossbow 1, these auxiliary pushing means including at least one member with elastic behavior (spring or hydraulic and/or pneumatic device or other) apt to accumulate elastic energy during the loading phase of the crossbow 1 and return it to said pushing means 30 during the projectile launch phase. Said auxiliary pushing means may be connected to the slide 25 and, in particular, be housed at the front of the stock 2, that is, in a position which is substantially opposite to said contrast means 50; in fact, the action of these auxiliary pushing means would be similar to the action exerted by the spring 53, but directed in the opposite direction and active in the phase in which these contrast means 50 are not operative.

These auxiliary pushing means may also be side by side to said contrast means 50, for example, by making that the spring 53 is joined in a stable manner to the end wall 51 and to the thrusting wall 54, so that it may accumulate elastic energy when the pushing arms 32 are brought from the neutral position to the maximum loading position and return it in the opposite direction.

As already said, in the described embodiment each pushing arm 32 forms a single part with a respective cam section 323. In alternative embodiments, the cam, i.e. the tensioning means apt to flex the bending member, is distinct from the pushing arm, i.e. the arm supporting the flexible pushing member 31 and the pulleys 145, 146; in other words, the cam and the pushing arm may be two distinct parts. In this case the axis of rotation of the cam and the axis of rotation of the pushing arm would be distinct. For example, the cam may be pivoted to the bending members 10 through a connection element 27 and the pushing arm may be directly pivoted to the stock 2. The transmission of the rotation movement from a cam to a respective arm (and vice versa) is realized for instance through a connecting rod which is pivoted to said cam and to said pushing arm.

The single flexible pushing member 37 may be replaced by two flexible pushing members, arranged on opposite side of the stock 2, each one having a first end associated to a respective second pulley 146 and a second end associated to the frame 61.

A second embodiment of a device for launching a projectile, in particular a crossbow, is shown in FIGS. 14A to 16, where it is indicated with the reference number 401. Elements having the same function and structure maintain the same reference number as in the embodiment previously described and, therefore, they are not described again in detail.

FIGS. 14A, 14B and 14C illustrate, respectively, the crossbow 401 in a neutral (rest) condition, in a loaded condition, and in a maximum discharge condition.

The crossbow 401 comprises retaining members or levers 420 to hold and constrain the bending members 10, through the connection elements 27, in a proper position with respect to the stock 2 during all operative phases of the crossbow 401, and, moreover, to determine the position and the displacement of fulcra of tensioning means during said phases.

In the example, four retaining members 420 are provided, i.e. two retaining members 420 on each side of the stock 2, and each one is associated to a respective bending member 10.

Each retaining member 420 comprises a first arm or lever 421, which is similar to the retaining lever 21 of the embodiment previously described and it is not described in detail again.

The first lever 421 is attached to a second lever 422 or side appendix, which laterally extends from the first lever 421 towards the outside of the stock 2; the first lever 421 and the second lever 422 of the same retaining member 420 rotate jointly around an axis 22, for instance being integral one and the other.

In the example, the first lever 421 and the second lever 422 slant each other and form an angle greater than 90 degrees.

Each pair of retaining members 420 on the same side of the stock 2 is pivotably mounted on a respective second flat protrusion 23 laterally extending from the stock 2, to which the second protrusion 23 is firmly joined or integral.

The flat protrusion 23 lies between the respective retaining members 420, which are pivoted to said second protrusion 23 by means of a pin 24 top-and-bottom extending from the second protrusion 23; in particular, the pin 24 is positioned in a seat or through hole 423 of the retaining member 420. To be more specific, said hole 423 is at the vertex of the angle formed by said first lever 421 and second lever 422, i.e. at first ends of them.

An axis of rotation 22 of the retaining member 420 corresponds to a longitudinal axis of said pin 24.

A second end 412 of each first retaining lever 421 is associated to the respective bending member 10, by means of a “C”-shaped housing 413 substantially similar to the “C”-shaped housing 213 previously described. A second end 425 of each second retaining lever 422 is associated to a flexible force member 437, for instance through a perforated cylinder 428 pivoted to both second retaining levers 422 on the same side of the stock 2.

The crossbow 401 has two flexible force member 437, one on each side of the stock 2, each of them having a first end 438 associated to a second pulley 146 and a second end 439 associated to a retaining member 420. The second end 439 of the flexible force member 437 is associated to the retaining member 420, in particular to its second lever 422, by means of said perforated cylinder 428 and a stopper 440 fastened to the flexible force member 437.

The loading phase and the launch phase for crossbow 401 are similar to the corresponding phases for crossbow 1 previously described; therefore they are not described in further detail.

The main difference is that, due to a slight rotation of the retaining members 420 during the loading/launch phase, the second retaining lever 422 goes towards/away from the respective pushing arm 32 and therefore a longer length or stretch of flexible force member 437 is to be wound/unwound on the second pulley 146, with respect to crossbow 1. Also the tension on the flexible force member 437 will be lower, so allowing for reduced cross section of the flexible force member 437 itself. Therefore the second pulley 146 can feature a smaller minimum radius and a larger maximum one; consequently, its eccentricity can be chosen in a larger interval making it easier to find the desired solution for getting the required force-draw curve.

Moreover the retaining members 420, and in particular the second retaining levers 422, cooperate with the bending members 10, in order to transmit a portion of energy to the flexible pushing member 31. In fact in the launch phase the rotation of the second retaining levers 422 towards the proximal end 205, moving away from the pushing arms 32 rotating towards the distal end 206, entails a further torque on the second pulleys 146, and then on the first pulleys 145, transmitted through the flexible force members 437. So the overall pushing action on the projectile is more balanced and a better structural efficiency is achieved. For instance, the pushing arms 32 can be lighter, because they are subjected to a lower stress.

A third embodiment of a device for launching a projectile, in particular a crossbow, is shown in FIGS. 17 and 18, where it is indicated with the reference number 501; it comprises further technical characteristics which may, however, be present alone or in combination or may be applied to the embodiments previously described. Elements having the same function and structure maintain the same reference number as in the embodiments previously described and, therefore, they are not described again in detail.

The crossbow 501 comprises two pushing arms 32, and the second end 322 of each pushing arm 32 supports a pair of pulleys 145, 146 rotatably associated to it. In the example, the pulleys 145, 146 are positioned at opposite side of the second end 322, i.e. a first pulley 145 is at top side of the pushing arm 32 and a second pulley 146 is at bottom side of the pushing arm 32.

In the example, the first pulley 145 is cylindrical, i.e. its side edge is circular and not eccentric with respect to a longitudinal axis 550 of a pivot 547 to which it is perpendicularly associated; the first pulley 145 and the pivot 547 rotate jointly.

Moreover, the side edge of the first pulley 145 has a helix-like track or groove 1452 which allows the winding of a plurality of turns of flexible pushing member 31.

The pivot 547 is housed in a first slot, or in a first hole 536 provided in the second end 322 of the pushing arm 32, and can rotate idle in this first hole 536 around the axis 550. The axis 550 makes translation movements together with the second end 322 of the respective pushing arm 32.

In the example, the second pulley 146 is eccentric and approximately semi-elliptical, i.e. its side edge and its groove 1461 have a semi-elliptical shape and a pivot 548 is perpendicularly fastened near the side edge at the major axis of the ellipse. A wheel 549 is perpendicularly fastened to the opposite side of the pivot 548. The wheel 549, the second pulley 146, and the pivot 548 rotate jointly.

The pivot 548 is housed in a second slot, or in a second through hole 537 provided in the second end 322 of the pushing arm 32, near the first hole 536; the pivot 548 can rotate idle in this second hole 537 around its longitudinal axis 551. The axis 551 makes translation movements together with the second end 322 of the respective pushing arm 32.

To be more specific, the second pulley 146 is at the bottom side of the pushing arm 32, whereas the wheel 549 is at the top side of the pushing arm 32, i.e. at the same side of the first pulley 145. Moreover, the wheel 549 is operatively connected to, and cooperates with, the pivot 547 of the first pulley 145, for instance being in contact with it, for a coordinated rotation of the first pulley 145 with the second pulley 146. For instance, the wheel 549 is a toothed wheel and the pivot 547 has a corresponding grooved or toothed portion, and the wheel 549 mates the pivot 547 through said toothings. Alternatively, the wheel 549 and the pivot 547 are frictionally coupled, i.e. they are mated through friction between the surface of the pivot 547 and the circumferential surface of the wheel 549.

The loading phase and the launch phase for crossbow 501 are similar to the corresponding phases for crossbow 401; therefore they are not described in further detail.

The main difference is that, due to the first pulley 145 and second pulley 146 rotating about different axes and coupled each other through the wheel 549 and the pivot 547, the first pulley 145 and the second pulley 146 on the same side rotate in opposite directions and have different revolution numbers.

In this embodiment the desired force-draw curve can be obtained by a proper design of the second pulley 146 and its eccentricity, while the first pulley 145 can be simply cylindrical.

Moreover, by modifying the diameter of the wheel 549 (or of the pivot 547 of the first pulley 145) it is also possible to vary the number of revolutions carried out by the first pulley 145 and the number of windings or turns of the flexible pushing member 31 on it, for a same shift of the pushing arm 32 along the flexible force member 437; in this way it is possible to vary the draw length while leaving the total width substantially unchanged. This is particularly advantageous for obtaining laterally compact devices with high power and reduced accelerations on the projectile.

As shown in FIG. 17 and in detail in FIG. 18, in the present embodiment the flexible force member 437 is not wound on the respective second pulley 146 when the crossbow 501 is in the neutral or rest condition; in fact the flexible force member 437 is fastened at the groove 1461 of the second pulley 146 so as to be simply tangential to its side edge in said condition. During the loading phase, the flexible force member 437 gets progressively wound on the second pulleys 146, whereas during the launch phase it gets progressively unwound from the second pulleys 146, as already described for the other embodiments.

During the stroke between the rest condition and the maximum discharge position, the rotation of the second pulley 146 gives additional distance between its rotation axis 551 and the corresponding second end 425 of the retaining side appendix 422 to which the other end 439 of the flexible force members 437 is fastened, due to the eccentricity of the second pulley 146 itself, so that a rotation movement of the pushing arms 32 towards the distal end 206 is allowed even if no flexible force member 437 is wound on the second pulleys 146. It is evident that this feature can be analogously applied also to other embodiments.

In another embodiment the first pulley 145 can be non-cylindrical and/or its groove 1452, apt to wind the flexible pushing member 31, can describe an irregular helix. This would allow greater design freedom in obtaining the desired operation in relation to the winding/unwinding action and in compensating altitude differences of said flexible pushing member 31 relative to the stock 2 during all operative phases. To the same end the plane on which the cam sections 323 of the arms 32 lie may be tilted along with at least some of the other components, for instance said plane may be tilted with respect to the projectile track 8 or to a proximal portion of the longitudinal development direction 201 of the stock 2.

A detail of a fourth embodiment of a device for launching a projectile is shown in FIG. 19, where it is represented in a first operative position. Said fourth embodiment, which is indicated with the reference number 601, comprises further technical characteristics which may, however, be present alone or in combination, or may be applied to the embodiments previously described. Elements having the same function and structure maintain the same reference number as in the embodiments previously described and, therefore, they are not described again in detail.

The crossbow 601 comprises retaining members 620 which are similar to the retaining members 420 of the crossbow 401 previously described. To be more specific, each retaining member 620 is pivoted to the stock 2 at a rotation axis 22 and comprises a first arm or lever 421 associated to a respective bending member 10 by means of a “C”-shaped housing 413, and a second lever 422 or side appendix, which laterally extends from the first lever 421 towards the outside of the stock 2. In the example, the first lever 421 and the second lever 422 slant each other and form an angle greater than 90 degrees. The first lever 421 and the second lever 422 of the same retaining member 620 rotate jointly around said axis 22, for instance being integral one and the other.

On each side of the stock 2, a return pulley 628 is rotatably associated to a retaining member 620; in particular, the return pulley 628 is interposed between second ends 425 of the second levers 422 on the same side, and is pivoted to them at a rotation axis 650.

A flexible force member 637 has a first end 638 a fastened or associated at the track 1461 of the second pulley 146, a second end 638 b fastened or associated at the pushing arm 32, in particular at a side protrusion 326 thereof, and a intermediate region 639 going around the return pulley 628, for approximately half a turn.

Said intermediate region 639, which is interposed between said first and second ends 638 a, 638 b, is housed in a track or groove 6281 of the return pulley 628. Therefore, said return pulley 628 is a tightener element of the flexible force member 637, i.e. it tights the flexible force member 637 and keeps the latter in tension; moreover it allows a sliding of the flexible force member 637 with respect to the retaining members 620.

Therefore, when the pushing arm 32 and the respective retaining member 620 rotate during all phases of operation of the crossbow 601, going towards/away each other, the winding/unwinding of the flexible force member 637 on/from the second pulley 146 is accompanied by a corresponding rotation of the return pulley 628 about its rotation axis 650.

With respect to previous embodiments, this arrangement approximately doubles the length of flexible force member 637 to be wound on the second pulley 146 and halves the tension on it, so allowing a reduction of its diameter and further increasing the scope for force-draw curve reshaping and providing a solution better suited for higher energies. In an alternative embodiment, each return pulley 628 is pivoted to the stock 2 instead of to a retaining member 620. For instance, the return pulleys 628 are pivoted to a frame similar to the frame 61 of the crossbow 1 previously described.

The principles at the basis of the present disclosure may be applied not just to a crossbow, but also to a bow, to a catapult, or to an apparatus for launching model aircraft or unmanned aerial vehicles or for devices for experimental purposes.

The subject of the present disclosure has been described so far with reference to its preferred embodiments. It is understood that there may be other embodiments which relate to the same inventive core, all included within the scope of the protection of the claims laid out below. 

1. A device for launching a projectile or a launch object in general, comprising: a stock having a longitudinal development direction between a rear or proximal end and a front or distal end, at least two bending members associated to said stock on opposite sides of it and having a preferential development direction, said bending members being apt to be subjected to flexing in order to accumulate and supply energy usable to launch said projectile, and released in a rest condition, tensioning means of said bending members, pushing means of said projectile apt to cooperate with said bending members, wherein said tensioning means comprise at least two cams arranged on opposite sides of the stock, each of which is pivoted at a respective first axis of rotation and is associated to at least one corresponding bending member, so that an angular displacement of a cam around said first axis of rotation determines a flexing action on said at least one corresponding bending member, and said pushing means comprise at least two pushing arms arranged on opposite sides of the stock and connected to each other through a flexible pushing member for pushing said projectile, wherein each of said pushing arms is pivoted at a respective axis of rotation and is apt to support a portion of said flexible pushing member, each of said pushing arms being operatively connected to a respective cam, so that a rotation of each pushing arm in a first rotation direction determines a flexing of said bending members by means of the respective cam during a loading phase of the device and that, during a launch phase of said projectile, a return of the bending members towards said rest condition determines, by means of the cam, a rotation in the opposite direction of each pushing arm, wherein said device further comprises a flexible force member for commanding a rotation of a pushing arm during said loading phase, and two pairs of pulleys arranged on opposite sides of the stock, wherein each pair comprises a first pulley interposed between a respective pushing arm and said flexible pushing member, and a second pulley interposed between the respective pushing arm and said flexible force member, said first pulley being rotatably connected to said second pulley for a coordinated rotation thereof around respective axes of rotation, so that in said rest condition the flexible pushing member is partially wound on the first pulley, and that during said loading phase the flexible pushing member gets unwound from the first pulley and the flexible force member gets wound on the second pulley, and that during said launch phase the flexible pushing member gets wound on the first pulley and the flexible force member gets unwound from the second pulley.
 2. The device according to claim 1, wherein said pushing arms are rotatable between a first maximum loading position, corresponding to a maximum flexing of the bending members, and a second maximum discharge position, between said first maximum loading position and said second maximum discharge position there being a neutral position at which said bending members are in said rest condition not presenting accumulated elastic energy.
 3. The device according to claim 2, wherein in said first maximum loading position the pushing arms are rotated towards said rear or proximal end of the stock, and in said second maximum discharge position the pushing arms are rotated in the direction of said front end of the stock.
 4. The device according to claim 1, wherein a portion of each of said bending members is associated idle to a portion of a respective cam, so as to allow said portion of bending member to make a translation movement together with said portion of cam, said translation movement taking place along a direction substantially orthogonal to said preferential development direction of said bending member.
 5. The device according to claim 4, wherein said portion of a respective cam is a slot in said respective cam at the respective first axis of rotation.
 6. The device according to claim 5, comprising a connection element positioned idle in said slot, said connection element comprising a connection member apt to move said portion of said at least one bending member.
 7. The device according to claim 6, wherein said connection element comprises two of said connection members, positioned symmetrically and connected to each other by a collar which is engaged in said slot of a respective cam, each of said connection members being apt to move said portion of a respective bending member.
 8. The device according to claim 1, further comprising retaining members for retaining said bending members, arranged on opposite side of the stock, each retaining member being pivoted to said stock and associated to at least one bending members.
 9. The device according to claim 6, further comprising retaining members for retaining said bending members, arranged on opposite sides of the stock, each retaining member being pivoted to said stock and associated to at least one bending members, wherein each retaining member is associated to a respective connection member.
 10. The device according to claim 1, wherein each of said pushing arms forms a single part with a respective cam and the axis of rotation of said pushing arm is coincident with said first axis of rotation of said respective cam.
 11. The device according to claim 1, wherein each of said pushing arms is connected to a respective cam by at least one connecting rod pivoted to said pushing arm and to said cam.
 12. The device according to claim 1, further comprising a pivot body of determined axis associated to the stock and positioned between the opposing cams, wherein a first of said cams and a second of said cams are hinged on said pivot body at a second axis of rotation.
 13. The device according to claim 12, further comprising a slide associated to the stock and positioned between the opposing cams, said slide comprising said pivot body and being apt to slide in said stock substantially parallel to said longitudinal development direction.
 14. The device according to claim 1, wherein said first pulley and/or said second pulley has/have an eccentric profile with respect to a respective axis of rotation.
 15. The device according to claim 1, wherein said first pulley and said second pulley supported by a same pushing arm are apt to rotate jointly around a same axis of rotation, said first pulley and second pulley being jointly associated to a common pivot.
 16. The device according to claim 1, wherein said first pulley and said second pulley supported by a same pushing arm are apt to rotate around distinct axis of rotation, said first pulley being jointly associated to a respective first pivot and said second pulley being jointly associated to a respective second pivot, wherein said coordinated rotation between said first pulley and said second pulley is obtained by means of a wheel jointly rotating with one of said first pivot and second pivot, and mating the other of said first pivot and second pivot.
 17. The device according to claim 16, wherein said mating is obtained by means of toothing or by means of friction coupling.
 18. The device according to claim 1, wherein a first length of said flexible force member is associated to a respective second pulley and a second length of said flexible force member is associated to a tightener element secured to the stock.
 19. The device according to claim 18, wherein said tightener element is a frame.
 20. The device according to claim 1, comprising retaining members for retaining said bending members, arranged on opposite side of the stock, each retaining member being pivoted to said stock and associated to at least one bending members, and further comprising two flexible force members arranged on opposite sides of said stock, wherein a flexible force member has a first length associated to a respective second pulley and a second length associated to a side appendix of a respective retaining member.
 21. The device according to claim 1, comprising retaining members for retaining said bending members, arranged on opposite sides of the stock, each retaining member being pivoted to said stock and associated to at least one bending members, and further comprising two flexible force members arranged on opposite sides of said stock and a return pulley pivoted to a side appendix of a respective retaining member, wherein a flexible force member has a first length associated to a respective second pulley, a second length associated to a respective pushing arm, and a intermediate length interposed between said first length and second length and going around said return pulley, said return pulley acting as a tightener element of said flexible force member.
 22. The device according to claim 1, further comprising two flexible force members arranged on opposite sides of said stock and further comprising a return pulley pivoted to said stock, wherein a flexible force member has a first length associated to a respective second pulley, a second length associated to a respective pushing arm, and a intermediate length interposed between said first length and second length and going around said return pulley, said return pulley acting as a tightener element of said flexible force member.
 23. The device according to claim 1, wherein said bending members are arranged so that said preferential development direction is substantially parallel to said longitudinal development direction of said stock.
 24. The device according to claim 23, wherein said bending members are positioned substantially adjacent to said stock.
 25. The device according to claim 1, wherein said at least two bending members, said at least two cams and said at least two pushing arms are arranged in a manner substantially symmetrical with respect to said stock.
 26. The device according to claim 1, comprising, on each side of said stock, at least two bending members opposite to each other with respect to a plane on which said cams lie, forming, overall, a group of at least four bending members symmetrical with respect to the longitudinal development direction of the stock.
 27. The device according to claim 1, further comprising contrast means associated to said stock, and operatively connected to said cams.
 28. The device according to claim 2, further comprising contrast means associated to said stock and operatively connected to said cams, wherein said contrast means are loaded so as to exert a force on said cams only when said pushing arms are beyond said neutral position towards said second maximum discharge position.
 29. The device according to claim 27, further comprising elastic means apt to bring back said pushing arms towards said neutral position.
 30. The device according to claim 13, further comprising contrast means associated to said stock, and operatively connected to said cams, wherein said contrast means and/or said elastic means are operatively connected to said slide.
 31. The device according to claim 1, further comprising auxiliary pushing means including at least one elastic member apt to accumulate energy during said loading phase of the device and apt to supply said energy to said pushing means during said launch phase of said projectile.
 32. The device according to claim 1, comprising associating means of at least one of said bending members to said stock, wherein said associating means are apt to prevent a translation of a tract of said at least one bending member in a direction orthogonal to said preferential development direction, and to allow said tract a flexing movement, and/or an angular displacement with respect to said stock, and/or a translation in said preferential development direction of said at least one bending member.
 33. The device according to claim 32, wherein said associating means are apt to prevent said translation in said orthogonal direction to a first tract and to a second tract of said at least one bending member, wherein said first tract and second tract correspond to end tracts thereof.
 34. The device according to claim 1, comprising associating means of at least one of said bending members to said stock, wherein said associating means are apt to join a tract of said at least one bending member to the stock in such a way as to prevent said tract both a translation with respect to the stock in said preferential development direction and in a direction orthogonal to said preferential development direction, and an angular displacement with respect to the stock.
 35. The device according to claim 1, wherein said device is a crossbow. 